ML20002A555
| ML20002A555 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/12/1980 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Robert Carlson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20002A548 | List: |
| References | |
| NUDOCS 8011200122 | |
| Download: ML20002A555 (2) | |
Text
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MORTHEAST UTHJTIES l
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May 12, 1980 Docket No. 50-245 Mr. Rob trt T. Carlson, Chief Reactor Censtruction and Engineering Support Branch U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406
References:
(1)
R.T. Carlson letter to W.G. Counsil dated April 17,1980 (2)
R.D. Ciatto letter to E.A. DeBarba, 3815A-1 dated January 10, 1980 Gentlemen:
Millstone Nuclear Power Station, Unit 1 Isolation Condenser System NRC Investication No. 50-245/80-02 In Reference (1), Northeast Nuclear Energy Company (NNECo) was requested to furnish information regarding the corrective action for an apparent item of non-compliance. Accordingly, the following is submitted in response.
Item II. A.1 (III D.l.C)
The Isolation Condenser System is not capable of withstanding seismic, blowcown, and water-hammer loads because of loose anchor bolts in pipe suppo rts.
The NRC investigation found that the licensee was aware of the loose anchor bolts, and had taken actions to repair these bolts.
However, the documentation of the inspection and the repairs was not in compliance with the-requirements of 10 CFR 50, Appendix B.
Resoonse The pipe inspections and bolt re-torqueing were performed under Job Orders R440-79 and 441-79.
Hanger repairs were performed under Job Order R4C9-79. The repair instructions issued on a plain sheet of paper were used to prepare the Job Order packages.
The Job Order System provides for the required reviews and approvals and satisfies the require-ments of 10 CFR 50 Appendix B.
0011200 122. -
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-j Mr. Robert T. Carls' U.S. Nuclear Regu) *ary Commission Page 2 0.3.C)
. Item II. A. 3
.it The Isolation Condenser System is not capable of withstanding seismic, blowdown, and water-hammer loads because of concrete cracking in. the drywell wall' at penetration X-10A.
The NRC investigators determined that the licensee was ' aware of the cracking of concrete in the drywell wall in the vicinity of penetration X-10A.
Howev tr, the investigators determined that the licensee's inspec-tion. and evaldation of these cracks after the water-hammer event were not adequats. The basis of licensee's determination of the-characteristic
.and the potential safety significance of the cracks was erroneously based on an earlier inadequate inspection and evaluation.
This was not in compliance with the requirement of 10 CFR 50, Appendix B.
Response
i At the time of the wcter-hammer incident, NNECo used the best engineering judgement available to 2 valuate the integrity of the Isolation Condenser System, including the concrete cracking in the drywell wall. Al though
- the evaluation was not as well documented as it should have' been, sub-sequent evaluations performed by Teladvne Engineering Services, (Reference 2),.
3l indicated that no structural damage had occurred and that only surface cracks between the grout and concrete interface were present, thus i
substantiating the original evaluation.
As a result of the investigation, NNECo Engineering Personnel are more acutely aware of the need to _ formally document any evaluations following a non-design plant event they perform and to identify the: criteria considered.
NNECo has expended a considerable amount of time and effort to support the investigation, evaluation, and subsequent repairs.
This effort satisfies the requirement for corrective ' action and has sufficiently sensitized the Engineering Staff to preclude recurrence.
Supporting documentation is available at the plant site for your review.
i 1
Very truly yours, NORTHEAST NUCLEAR ENERGY CCMPANY 4
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i, W. G. Counsil Vice President yr s
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